Biodiversity Gain Sites in England
Biodiversity gain sites in England are locations where new or improved habitats are created to achieve England's Biodiversity Net Gain (BNG) requirement. Developers must now achieve at least a 10% increase in the biodiversity of a parcel of land following its development. If this is not possible within the development site itself - by creating or enhancing its existing habitats - the biodiversity gain must be delivered elsewhere, by developers paying for the same types of habitat at a different location. For this purpose, Biodiversity Gain Sites (BGS) have been made available by landowners, who will sell biodiversity units to developers.
You can search the list of sites here in various ways to find the most appropriate one for your needs.
How we gathered the data
The data included in the list of biodiversity gain sites given here is compiled from various sources:
1. The BGS Register
Biodiversity Gain Site (BGS) Register
BGS Register Search This is the source of the base data. Until the data is provided publicly in computer-readable form, the data is extracted from the json files used to render the HTML website.
2. Responsible Bodies
Details of the responsible bodies are taken from the .GOV list Conservation covenants: list of designated responsible bodies.
3. Locations
BGS Site locations are given but the precise location of allocations addresses has to be deduced using the Google Geocoder. Where the address is incomplete or missing, the location falls back to the centre point of the LPA.
4. Local Planning Authorities (LPAs)
The boundaries of all the English LPAs are used to identify the LPA in which a development site or BGS site is located
5. National Character Areas (NCAs)
The boundaries of NCAs are used to identify the NCA in which a development site or BGS site is located.
6. Local Nature Recovery Strategy (LNRS)
The boundaries of LNRS sites are used to identify the LNRS in which a development site or BGS site is located
7. Lower Layer Super Output Areas (LSOAs)
A Lower Layer Super Output Area (LSOA) is a geographic statistical unit in the UK, used for the publication of small-area statistics. Each LSOA comprises between 4 and 5 Output Areas (OAs) and contains 1,000 to 3,000 people (between 400 and 1,200 households).
8. Index of Multiple Deprivation (IMD)
Levels of deprivation are shown in deciles - between 1 to 10 - with band 1 being within the most deprived 10% areas of the country and band 10 being within the least deprived 10% of the country.
How we processed the data
We enhanced the base data extracted from the BGS register in a number of ways:
1. Site Habitats - HU calculations
Baseline parcels are as per the standard formula – Habitat Unit (HU) = Habitat area/length (of parcel) x Distinctiveness (of Habitat) x Condition (of parcel) x Strategic Significance (where SS is set to Low, 1).
2. Improvements
Created parcels - HU = Habitat area/length (of parcel) x Distinctiveness (of Habitat) x Condition (of parcel) x Strategic Significance (of parcel – low, 1) x Temporal Risk (of Habitat and Condition) x Difficulty factor (of the Habitat) x Spatial Risk (Low, 1)
Enhanced parcels - HU is not computed because no connection can be made back to the baseline habitat parcel's value.
Refreshing the data
We refresh Defra's BGS data hourly.
Acknowledgements
Digital boundaries and reference maps:
© Natural England 2023. Contains OS data © Crown Copyright [and database right] 2023
Contains GeoPlace data © Local Government Information House Limited copyright and database right 2023
Exports
The site summary is now available as a WFS map layer on the WFS service https://bristoltrees.space/wfs/wfs-server.xq?SERVICE=WFS&REQUEST=GetCapabilities.
Development
This is an open-source project designed and built by Bristo Tree Forum using Next.js.
It is based on data sourced from Natural England's Biodiversity gain sites register.
You can view the source code at GitHub.
Privacy Policy (last updated 5 Oct 2025)
1. Data Controller
The data controller responsible for this website is:
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Email: BGS_Enquiries@bristoltreeforum.org
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